I just moved into an apartment in Brooklyn that is a duplex with the ground floor serving as the top floor of the apt, and the basement (converted with wood flooring and sheetrock walls) serving as the downstairs and bedroom.

I've been looking into a lot of the requirements for basement apartments but wasn't sure if my apartment must meet all those conditions as it's part of a duplex. The basement does not have any windows, but has a door that leads to stairs to the backyard (the upstairs also has a door leading to the backyard). It also has an open spiral staircase leading to the upstairs, so it's not entirely closed off.

Also, I looked up the certificate of occupancy for the building and it mentions 2 first floor duplexes, but does not mention that the basements are being used as floors in the duplexes. Is that correct or should the C of O specifically list the basement?